Domestic installation of swimming pools and spas has increased dramatically over the past several years. However, the use of pools and spas in which water is continually reused requires the use of treatments and filters to maintain both health and aesthetic appeal. Standard spas and swimming pools employ a bi-directional flow system for circulating and filtering water. In standard operation, a pump is used to move water in a given direction through a filter where particulate matter and other unwanted debris is removed. Over time, the filter builds up an excessive accumulation of waste matter thereby impairing its effectiveness as a filter. In order to clear the filter of such debris, water flow through the filter is reversed to dislodge the matter and eliminate it from the system, a process known as backwashing. Known filter systems tend to be disadvantageous in that they require involved assembly and disassembly in order to effect filter changes.
Reversal of water flow is generally accomplished by means of a valve that can be adjusted to provide different flow directions. The rotary valve is an example of one valve type that has been used to achieve reversible flows. Examples of rotary valves are disclosed in U.S. Pat. Nos. 37,786; 3,590,872; 4,371,003; Re 24,055; and Re 30,224. Generally speaking, prior art rotary valves are complicated constructions that are expensive and time-consuming to produce. The rotor is frequently imbedded within the valve body, requiring disassembling of the valve to effect repair. Further, known rotary valves require complicated sealing means to guard against leaks and loss of pressure.
There is a need therefore for a rotary valve within a filter system that can be easily and quickly accessed for removing and replacing filters. There is an additional need for a rotary valve which is simply constructed and easily accessible for efficient repair and replacement. Finally there is a need for a rotary valve that does not require complex or expensive sealing means.